Assembly of engine cylinders and manifolds



Dec. 10, 1946.

LAW

W. A. LEDWITH ASSEMBLY OF ENGINE CYLINDERS AND MANIFOLDS Filed May 11, 1943 2 Sheets-Sheet 1 Maw- ATTORNEY Dec. 10, 1946; w. A. LEDWITH 2,412,344

' ASSEMBLY OF ENGINE CYLINDERS AND MANIFOLDS Filed May- 11, 1943 2 Sheets-Sheet 2 FIG. 2

INV 29R ATTORNEY Patented Dec. 10, 1946 ASSEMBLY OF ENGINE CmNDERS AND MANIFOLDS Walter A. Ledwith, Hartford, com, assignor to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Application May 11, 1943, Serial No. 486,622

Claims. (o1. 123-493) This invention relates to the assembly of an engine cylinder and manifolds for an opposed piston engine, and particularly to the assembly of a free-piston engine-and-compressor unit..

The weight 01' an opposed piston engine foruse in an aircraft power plant must be reduced. to a minimum in order to obtain a low weight for the entire power plant. An object of this invention is to assemble the parts of the engine cylinder in such a way as to minimize the weight of the parts.

, air leaves the cylinders through discharge valves 42, also at opposite ends of the compressor cylinders; and passes through scavenge manifold 44 through spaced ports 48 and 48 which are uncovered by pistons l2 and M at the end of the power stroke thereby permitting air to be blown through the engine cylinder and spaced exhaust orts 58 and 52 into exhaust manifold 54'.

Opposed piston engines have inlet and exhaust ports covered and uncovered by the pistons during their reciprocation. Manifolds surrounding the engine cylinder direct scavenge air into the engine cylinder and collect the exhaust gas from the exhaust ports. is the mounting of a part, at least, of the manifoldson the engine cylinder by the same structure that holds the engine cylinder in. alignment with the supporting structure. a

Another feature of this invention is the as semblyvof an engine cylinder and associated parts by one or more .turnbuckles. Another feature is the use of turnbuckles in-connecting the engine cylinder to a surrounding housing.

Other objects and advantages will be apparent from the specification and claims and from the. accompanying drawings which illustrate what is now considered to be a preferred embodiment of the invention.

Fig. 1 is a sectional view through the freepiston engine-and-compressor unit.

Fig. 2 is a sectional view on a larger scale of the engine cylinder assembly.

' The unit shown includes an engine cylinder l8 having reciprocating pistons l2 and I4 to which compressor pistons l8 and i8 in cylinders 28 and 22 are integrally connected. Sleeves 24 and 26 attached to the compressor pistons complete the reciprocating piston assemblies. The sleeves in combination with stationary pistons 28 and 38 form air spring cylinders.

The piston assemblies are moved apart by the burning of fuel injected into engine cylinder l8 by one or more devices 32. Air compressed in the air spring cylinders on the power stroke returns the piston assemblies. The assemblies are always maintained at equal distances from the center of the engine cylinder by a linkage which may include racks 34 on the compressor pistons meshing with a pinion 38.

Intake manifold 38 conducts air to intake valves 48 through which air alternately enters opposite ends of the compressor cylinders. The compressed A feature of this invention Ring-shaped exhaust ducts 58 and 68 surround the enginescylinder and collect the gases discharging through exhaust ports 58 and 52. 'These ducts are connected to exhaust manifold 54.

A housing 82, Fig. 2, surrounds the engine cylinder between its ends and has at least one radial chamber 64 which receives injection device 32.

The exhaust ducts 58 and 68 are held against housing 82 by turnbuckles 68 and 18. Each turnbuckle is in the form of a ring having right and left threads 12 and 14 on its inner surface. These threads engage cooperating threads 16 and 18 on housing and duct respectively, and turning the ring brings the duct and housing into assembled position. Threads 16 and 18 are of different pitch so that ring 68 or 18 may be started on duct 58 or 68 before it is started on the housing.

The engine cylinder I 8, which may be liquid cooled, has an inner sleeve-like element 88 extending the entire length of the engine cylinder and having shoulders 82 and 84 at its opposite ends. Outer cylinder elements 86 and 88 surrounding the inne sleeve element and extending toward each other in substantial alignment,

have inwardly extending flanges 98 and 92 at their outer ends, engaging the shoulders on the ends of the inner element 88. The flanges '98 and 92 may be brazed to shoulders 82 and 84 for a positive seal.

The inner ends of outer elements 88 and 88 have shoulders 94 and 96, respectively, which are engaged by a part of the surrounding exhaust ducts 58 and 68. Turnbuckles 68 and 18 which engage ducts 58 and 68 thus hold these ducts in position and also hold the assembled cylinder elements in radial position within, and in.axial alignment in surrounding housing 62. r

A shield may be positioned between the outer and inner cylinder elements for directing the cooling liquid in predetermined paths. This shield may comprise cylindrical sleeves 98 and I88 attached at their outer ends to the oute surface of the inner cylinder element. The inner ends of these sleeves may overlap near the center of the engine cylinder as indicated at I82. The sleeves have notches I84 and 186 to receive boss I08 on inner element 80 where the injection device is mounted.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as defined by the following claims.

I claim:

1. A cylinder construction including an inner cylinder element having shoulders at its ends, outer cylinder elements overlying said inner cylinder and having shoulders cooperating with said first shoulders, the inner ends of said elements being adjacent each other, and a turnbuckle in the form of a threaded ring extending across said elements for holding each outer element in predetermined position.

2. A cylinder construction for fluid cooled engines, a cylinder wall, outer elements extending around said wall and spaced therefrom, the outer end of each element engaging an end of the wall, in combination with cooperating threaded rings extending around said elements for drawing-said elements toward each other and for holding the ends of the elements against the ends-of the wall.

3.-In a cylinder construction for fluid cooled engines, a cylinder wall having shoulders at its ends, outer elements extending around said wall and spaced therefrom, each outer element having a shoulder cooperating with one end shoulder on the wall, the adjoining edges of the outer elements being spaced from each other, in combination with threaded rings extending around said outer elements for drawing'said outer elements toward each other and for holding the shoulders on said elements against the shoulders on the wall.

4. In a cylinder construction for fluid cooled engines, a cylinder wall having shoulders at its ends, outer elements extending around said wall and spaced therefrom, each outer element having a. shoulder cooperating with one shoulder on the wall, the adjoining edges of the outer elements being spaced from each other, and a housing around said wall in combination with tumbuckle means in the form of rings extending around said outer elements for drawing said outer elements towards each other and into desired position with respect to the housing.

5. In a cylinder construction for fluid cooled engines, a cylinder wall having shoulders at its ends, outer elements extending around said wall and in spaced relation therefrom, each outer element having a shoulder cooperating with one shoulder on the wall, the adjoining edges of the outer elements being spaced from each other, a housing around said wall, threads on the housing and other threads associated with each element, and rings constituting turnbuckles having their opposed threads engaging the threads associated with said elements and on the housing for urging the elements and the housing toward each at er.

6. In a cylinder construction, a cylinder having ports, a manifold extending around said ports, in combination with turnbuckle means for securing the manifold to the cylinder.

7. In a cylinder construction, a cylinder having ports, a manifold extending around said ports, and a housing around said cylinder in compiston engine, an inner cylinder element, outerelements extending around said inner element from opposite ends thereof, the inner ends of said outer elements being spaced from each other, a housing extending around the center-part of said inner cylinder element and having a cylindrical surface with which the inner ends of the outer cylinder elements engage, said inner and.

outer cylinder elements having aligned ports adjacent opposite ends of the inner element, manifolds extending around at least some of the ports adjacent each end of the inner element, each of said manifolds havingthreads thereon and engaging endwise with a part of the adjoining outer cylinder element, said housing also having threads thereon adjacent each end, and'turnbuckles in the form of rings extending around the housing and engaging the threads on the housing and the threads on the adjacent manifold for holding said manifolds against the outer cylinder elements and for holding the outer cylinder elements in position.

10. In a cylinder construction, a cylinder having ports therethrough, adjacent each end, manifolds extending around the cylinder and enclosing at least some of the ports adjacent each end, a housing extending centrally around the cylinder and having spaced sets of threads thereon, said housing also having a cylindrical wall, said cylinder having cylindrical outer surfaces engaging with said cylindrical wall on the housing so that the cylinder is piloted within the housing, said cylinder also having spaced shoulders thereon engageable endwise by the surrounding manifolds, each of said manifolds having a'set of threads thereon and a ring engaging each set oi threads on the housing, and the set of 

